To determine the structural and functional roles of lipids and the mechanisms of biosynthesis of lipids in trypanosomatid flagellates by: 1) a complete analysis of the lipids of intact flagellates, 2) observation of the ability of intact flagellates to incorporate and to modify isotopically-labeled lipids, 3) isolation of flagellate organelles (kinetoplast-mitrochondrion, flagellum, etc.) and characterization of their lipids, 4) observation of the distribution of isotopically-labeled lipids among these organelles. Bibliographic references: Beach, D.H., Sherman, I. & Holz, G.G., Jr. 1975. Octadecenoic fatty acids and their relationship to hemolysis in Plasmodium lophurae-infected ducklings. J. Parasitol. Beach, D.H., Sherman, I. & Holz, G.G., Jr. 1975. Lipids of P. lophurae and of normal and infected Peking duck erythrocytes and plasma. J. Parasitol.